67Li( pi +,pd)3,4He reactions at 59.4 MeV.

Abstract

The (..pi../sup +/,pd) reactions on /sup 6/Li and /sup 7/Li have been studied at T/sub ..pi../ = 59.4 MeV. Triple- and single-differential cross sections for these reactions are presented. The data are fitted to a T matrix and compared to the /sup 3/H(..pi../sup +/,p)/sup 2/H reaction. A model in which the pion interacts and is absorbed on a ''quasi-triton'' cluster describes the main features of the data very well. An extrapolation of our data into unmeasured regions of phase space suggests that about 8% of the pion absorption cross section on /sup 6/Li at 59.4 MeV goes into the (..pi../sup +/,pd) channel. The /sup 7/Li(..pi../sup +/,pd)/sup 4/He(2 /sup -/) transition at 22.1 MeV excitation appears to be strongly populated. This is a surprise because it is not seen in the /sup 7/Li(p,..cap alpha..)/sup 4/He reaction.